One of the key advantages of modem optical communications systems is that a single optical waveguide is able to support a variety of distinct optical signals, each having a somewhat different characteristic wavelength range. Further, when the optical signals are provided in a same wavelength communication band a single optical amplifier supports the amplification of each of these signals individually. The deployment of this technology has facilitated a reduction in cost of transmitting data over long distances. In U.S. Pat. No. 5,535,050 by Suyama an optical amplifier featuring “an optical fiber which may be doped with a rare earth element.” (reference Abstract of Suyama.)
Optical amplifiers support a variety of complex optical networking devices. For example in U.S. Pat. No. 6,424,445 by Tsushima et al. optical amplifiers are used to support an optical repeater featuring an optical cross-connect. The device of Tsushima et al. clearly demonstrates that optical amplifiers have uses that are not restricted to propagating optical data over long distances.
Unfortunately, the cost of optical amplifiers, such as erbium doped fibre amplifiers (EDFA) and yttrium doped fibre amplifiers (YDFA) is still very high because a variety of the components used in their design remain difficult to produce commercially.
It would be beneficial to provide a less expensive optical amplifier that provides higher reliability than conventional EDFAs and YDFAs with comparable performance.